Gli ultrasuoni nella diagnosi della fragilità ossea.

Recently, a proposal has been made to evaluate bone fragility in osteoporotic women by measuring ultrasound transmission velocity at the patella. Theoretically, sound transmission velocity depends on both bone mass and other factors which are not mass-dependent--e.g. bone architecture. Ultrasound transmission technique was thus tested for the capability of evaluating bone fragility factors, which are not mass-dependent, in the screening of osteoporotic women. To this purpose, the sound velocity at the patella of 31 healthy women was compared with that of 62 osteoporotic women with spontaneous vertebral fractures having similar bone mineral content. In 31 cases bone mineral content was similar to that of healthy women at the middle radius, and in 31 at the distal radius. Sound transmission velocity was significantly lower in osteoporotic than in healthy women. Fifty-two per cent of healthy women was correctly selected by US, relative to the risk threshold, versus 13% with bone mineral densitometry. This finding suggests that US is capable of distinguishing normal from osteoporotic women having similar bone mineral content, which means that non-mass-dependent factors may affect US velocity in the bone. Since the measurement were taken in various sites, different for US and bone densitometry, our results need confirmation in further studies where measurements are taken in the same sites.